diff --git a/cmd/zpool/zpool_main.c b/cmd/zpool/zpool_main.c
index bc91771376..3679b4ee2d 100644
--- a/cmd/zpool/zpool_main.c
+++ b/cmd/zpool/zpool_main.c
@@ -69,6 +69,8 @@ static int zpool_do_online(int, char **);
 static int zpool_do_offline(int, char **);
 static int zpool_do_clear(int, char **);
 
+static int zpool_do_reguid(int, char **);
+
 static int zpool_do_attach(int, char **);
 static int zpool_do_detach(int, char **);
 static int zpool_do_replace(int, char **);
@@ -128,7 +130,8 @@ typedef enum {
 	HELP_EVENTS,
 	HELP_GET,
 	HELP_SET,
-	HELP_SPLIT
+	HELP_SPLIT,
+	HELP_REGUID
 } zpool_help_t;
 
 
@@ -172,6 +175,7 @@ static zpool_command_t command_table[] = {
 	{ "import",	zpool_do_import,	HELP_IMPORT		},
 	{ "export",	zpool_do_export,	HELP_EXPORT		},
 	{ "upgrade",	zpool_do_upgrade,	HELP_UPGRADE		},
+	{ "reguid",	zpool_do_reguid,	HELP_REGUID		},
 	{ NULL },
 	{ "history",	zpool_do_history,	HELP_HISTORY		},
 	{ "events",	zpool_do_events,	HELP_EVENTS		},
@@ -254,6 +258,8 @@ get_usage(zpool_help_t idx) {
 		return (gettext("\tsplit [-n] [-R altroot] [-o mntopts]\n"
 		    "\t    [-o property=value] <pool> <newpool> "
 		    "[<device> ...]\n"));
+	case HELP_REGUID:
+		return (gettext("\treguid <pool>\n"));
 	}
 
 	abort();
@@ -3206,6 +3212,52 @@ zpool_do_clear(int argc, char **argv)
 	return (ret);
 }
 
+/*
+ * zpool reguid <pool>
+ */
+int
+zpool_do_reguid(int argc, char **argv)
+{
+	int c;
+	char *poolname;
+	zpool_handle_t *zhp;
+	int ret = 0;
+
+	/* check options */
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		case '?':
+			(void) fprintf(stderr, gettext("invalid option '%c'\n"),
+			    optopt);
+			usage(B_FALSE);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	/* get pool name and check number of arguments */
+	if (argc < 1) {
+		(void) fprintf(stderr, gettext("missing pool name\n"));
+		usage(B_FALSE);
+	}
+
+	if (argc > 1) {
+		(void) fprintf(stderr, gettext("too many arguments\n"));
+		usage(B_FALSE);
+	}
+
+	poolname = argv[0];
+	if ((zhp = zpool_open(g_zfs, poolname)) == NULL)
+		return (1);
+
+	ret = zpool_reguid(zhp);
+
+	zpool_close(zhp);
+	return (ret);
+}
+
+
 typedef struct scrub_cbdata {
 	int	cb_type;
 	int	cb_argc;
diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 72d511b068..0f0ab60dde 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 /*
@@ -260,6 +261,7 @@ ztest_func_t ztest_vdev_LUN_growth;
 ztest_func_t ztest_vdev_add_remove;
 ztest_func_t ztest_vdev_aux_add_remove;
 ztest_func_t ztest_split_pool;
+ztest_func_t ztest_reguid;
 
 uint64_t zopt_always = 0ULL * NANOSEC;		/* all the time */
 uint64_t zopt_incessant = 1ULL * NANOSEC / 10;	/* every 1/10 second */
@@ -290,6 +292,7 @@ ztest_info_t ztest_info[] = {
 	{ ztest_fault_inject,			1,	&zopt_sometimes	},
 	{ ztest_ddt_repair,			1,	&zopt_sometimes	},
 	{ ztest_dmu_snapshot_hold,		1,	&zopt_sometimes	},
+	{ ztest_reguid,				1,	&zopt_sometimes },
 	{ ztest_spa_rename,			1,	&zopt_rarely	},
 	{ ztest_scrub,				1,	&zopt_rarely	},
 	{ ztest_dsl_dataset_promote_busy,	1,	&zopt_rarely	},
@@ -326,6 +329,7 @@ typedef struct ztest_shared {
 	uint64_t	zs_vdev_aux;
 	uint64_t	zs_alloc;
 	uint64_t	zs_space;
+	uint64_t	zs_guid;
 	kmutex_t	zs_vdev_lock;
 	krwlock_t	zs_name_lock;
 	ztest_info_t	zs_info[ZTEST_FUNCS];
@@ -4804,7 +4808,7 @@ ztest_ddt_repair(ztest_ds_t *zd, uint64_t id)
 
 	object = od[0].od_object;
 	blocksize = od[0].od_blocksize;
-	pattern = spa_guid(spa) ^ dmu_objset_fsid_guid(os);
+	pattern = zs->zs_guid ^ dmu_objset_fsid_guid(os);
 
 	ASSERT(object != 0);
 
@@ -4876,6 +4880,31 @@ ztest_scrub(ztest_ds_t *zd, uint64_t id)
 	(void) spa_scan(spa, POOL_SCAN_SCRUB);
 }
 
+/*
+ * Change the guid for the pool.
+ */
+/* ARGSUSED */
+void
+ztest_reguid(ztest_ds_t *zd, uint64_t id)
+{
+	ztest_shared_t *zs = ztest_shared;
+	spa_t *spa = zs->zs_spa;
+	uint64_t orig, load;
+
+	orig = spa_guid(spa);
+	load = spa_load_guid(spa);
+	if (spa_change_guid(spa) != 0)
+		return;
+
+	if (zopt_verbose >= 3) {
+		(void) printf("Changed guid old %llu -> %llu\n",
+		    (u_longlong_t)orig, (u_longlong_t)spa_guid(spa));
+	}
+
+	VERIFY3U(orig, !=, spa_guid(spa));
+	VERIFY3U(load, ==, spa_load_guid(spa));
+}
+
 /*
  * Rename the pool to a different name and then rename it back.
  */
@@ -5307,6 +5336,7 @@ ztest_run(ztest_shared_t *zs)
 {
 	kt_did_t *tid;
 	spa_t *spa;
+	objset_t *os;
 	kthread_t *resume_thread;
 	uint64_t object;
 	int error;
@@ -5340,6 +5370,10 @@ ztest_run(ztest_shared_t *zs)
 	spa->spa_debug = B_TRUE;
 	zs->zs_spa = spa;
 
+	VERIFY3U(0, ==, dmu_objset_hold(zs->zs_pool, FTAG, &os));
+	zs->zs_guid = dmu_objset_fsid_guid(os);
+	dmu_objset_rele(os, FTAG);
+
 	spa->spa_dedup_ditto = 2 * ZIO_DEDUPDITTO_MIN;
 
 	/*
diff --git a/include/libzfs.h b/include/libzfs.h
index 86e23ac327..096910bb19 100644
--- a/include/libzfs.h
+++ b/include/libzfs.h
@@ -21,7 +21,8 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright 2010 Nexenta Systems, Inc. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #ifndef	_LIBZFS_H
@@ -250,6 +251,7 @@ typedef struct splitflags {
  */
 extern int zpool_scan(zpool_handle_t *, pool_scan_func_t);
 extern int zpool_clear(zpool_handle_t *, const char *, nvlist_t *);
+extern int zpool_reguid(zpool_handle_t *);
 
 extern int zpool_vdev_online(zpool_handle_t *, const char *, int,
     vdev_state_t *);
diff --git a/include/sys/fm/fs/zfs.h b/include/sys/fm/fs/zfs.h
index 4571939d2d..6e652df989 100644
--- a/include/sys/fm/fs/zfs.h
+++ b/include/sys/fm/fs/zfs.h
@@ -39,6 +39,7 @@ extern "C" {
 #define	FM_EREPORT_ZFS_CONFIG_SYNC		"config.sync"
 #define	FM_EREPORT_ZFS_POOL			"zpool"
 #define	FM_EREPORT_ZFS_POOL_DESTROY		"zpool.destroy"
+#define FM_EREPORT_ZFS_POOL_REGUID		"zpool.reguid"
 #define	FM_EREPORT_ZFS_DEVICE_UNKNOWN		"vdev.unknown"
 #define	FM_EREPORT_ZFS_DEVICE_OPEN_FAILED	"vdev.open_failed"
 #define	FM_EREPORT_ZFS_DEVICE_CORRUPT_DATA	"vdev.corrupt_data"
diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
index 2b6abbf1bd..032a952afd 100644
--- a/include/sys/fs/zfs.h
+++ b/include/sys/fs/zfs.h
@@ -22,6 +22,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 /* Portions Copyright 2010 Robert Milkowski */
@@ -786,6 +787,7 @@ typedef enum zfs_ioc {
 	ZFS_IOC_DIFF,
 	ZFS_IOC_TMP_SNAPSHOT,
 	ZFS_IOC_OBJ_TO_STATS,
+	ZFS_IOC_POOL_REGUID,
 	ZFS_IOC_EVENTS_NEXT,
 	ZFS_IOC_EVENTS_CLEAR,
 } zfs_ioc_t;
@@ -855,6 +857,7 @@ typedef enum {
  *	ESC_ZFS_RESILVER_START
  *	ESC_ZFS_RESILVER_END
  *	ESC_ZFS_POOL_DESTROY
+ *	ESC_ZFS_POOL_REGUID
  *
  *		ZFS_EV_POOL_NAME	DATA_TYPE_STRING
  *		ZFS_EV_POOL_GUID	DATA_TYPE_UINT64
diff --git a/include/sys/spa.h b/include/sys/spa.h
index c9028fb093..9de5736edb 100644
--- a/include/sys/spa.h
+++ b/include/sys/spa.h
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #ifndef _SYS_SPA_H
@@ -579,6 +580,7 @@ extern void spa_altroot(spa_t *, char *, size_t);
 extern int spa_sync_pass(spa_t *spa);
 extern char *spa_name(spa_t *spa);
 extern uint64_t spa_guid(spa_t *spa);
+extern uint64_t spa_load_guid(spa_t *spa);
 extern uint64_t spa_last_synced_txg(spa_t *spa);
 extern uint64_t spa_first_txg(spa_t *spa);
 extern uint64_t spa_syncing_txg(spa_t *spa);
@@ -612,6 +614,7 @@ extern uint64_t spa_get_random(uint64_t range);
 extern uint64_t spa_generate_guid(spa_t *spa);
 extern void sprintf_blkptr(char *buf, const blkptr_t *bp);
 extern void spa_freeze(spa_t *spa);
+extern int spa_change_guid(spa_t *spa);
 extern void spa_upgrade(spa_t *spa, uint64_t version);
 extern void spa_evict_all(void);
 extern vdev_t *spa_lookup_by_guid(spa_t *spa, uint64_t guid,
diff --git a/include/sys/spa_impl.h b/include/sys/spa_impl.h
index 3f5cd9a73d..1317a9fc64 100644
--- a/include/sys/spa_impl.h
+++ b/include/sys/spa_impl.h
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #ifndef _SYS_SPA_IMPL_H
@@ -136,7 +137,8 @@ struct spa {
 	objset_t	*spa_meta_objset;	/* copy of dp->dp_meta_objset */
 	txg_list_t	spa_vdev_txg_list;	/* per-txg dirty vdev list */
 	vdev_t		*spa_root_vdev;		/* top-level vdev container */
-	uint64_t	spa_load_guid;		/* initial guid for spa_load */
+	uint64_t	spa_config_guid;	/* config pool guid */
+	uint64_t	spa_load_guid;		/* spa_load initialized guid */
 	list_t		spa_config_dirty_list;	/* vdevs with dirty config */
 	list_t		spa_state_dirty_list;	/* vdevs with dirty state */
 	spa_aux_vdev_t	spa_spares;		/* hot spares */
diff --git a/lib/libspl/include/sys/sysevent/eventdefs.h b/lib/libspl/include/sys/sysevent/eventdefs.h
index c4494f778c..50ab0ca4d3 100644
--- a/lib/libspl/include/sys/sysevent/eventdefs.h
+++ b/lib/libspl/include/sys/sysevent/eventdefs.h
@@ -21,6 +21,7 @@
 /*
  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #ifndef	_SYS_SYSEVENT_EVENTDEFS_H
diff --git a/lib/libzfs/libzfs_pool.c b/lib/libzfs/libzfs_pool.c
index 7b78f25f00..bb184ed688 100644
--- a/lib/libzfs/libzfs_pool.c
+++ b/lib/libzfs/libzfs_pool.c
@@ -21,6 +21,8 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <ctype.h>
@@ -2948,6 +2950,26 @@ zpool_vdev_clear(zpool_handle_t *zhp, uint64_t guid)
 	return (zpool_standard_error(hdl, errno, msg));
 }
 
+/*
+ * Change the GUID for a pool.
+ */
+int
+zpool_reguid(zpool_handle_t *zhp)
+{
+	char msg[1024];
+	libzfs_handle_t *hdl = zhp->zpool_hdl;
+	zfs_cmd_t zc = { "\0", "\0", "\0", "\0", 0 };
+
+	(void) snprintf(msg, sizeof (msg),
+	    dgettext(TEXT_DOMAIN, "cannot reguid '%s'"), zhp->zpool_name);
+
+	(void) strlcpy(zc.zc_name, zhp->zpool_name, sizeof (zc.zc_name));
+	if (zfs_ioctl(hdl, ZFS_IOC_POOL_REGUID, &zc) == 0)
+		return (0);
+
+	return (zpool_standard_error(hdl, errno, msg));
+}
+
 /*
  * Convert from a devid string to a path.
  */
diff --git a/man/man8/zpool.8 b/man/man8/zpool.8
index ba55b981fb..5015e30fd2 100644
--- a/man/man8/zpool.8
+++ b/man/man8/zpool.8
@@ -3,7 +3,8 @@
 .\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License. You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.
 .\" See the License for the specific language governing permissions and limitations under the License. When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the
 .\" fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
-.TH zpool 8 "8 Apr 2011" "ZFS pool 28, filesystem 5" "System Administration Commands"
+.\" Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+.TH zpool 8 "10 July 2012" "ZFS pool 28, filesystem 5" "System Administration Commands"
 .SH NAME
 zpool \- configures ZFS storage pools
 .SH SYNOPSIS
@@ -95,6 +96,11 @@ zpool \- configures ZFS storage pools
 \fBzpool online\fR \fIpool\fR \fIdevice\fR ...
 .fi
 
+.LP
+.nf
+\fBzpool reguid\fR \fIpool\fR
+.fi
+
 .LP
 .nf
 \fBzpool remove\fR \fIpool\fR \fIdevice\fR ...
@@ -1376,6 +1382,17 @@ Expand the device to use all available space. If the device is part of a mirror
 .ne 2
 .mk
 .na
+\fB\fBzpool reguid\fR \fIpool\fR
+.ad
+.sp .6
+.RS 4n
+Generates a new unique identifier for the pool.  You must ensure that all devices in this pool are online and
+healthy before performing this action.
+.RE
+
+.sp
+.ne 2
+.na
 \fB\fBzpool remove\fR \fIpool\fR \fIdevice\fR ...\fR
 .ad
 .sp .6
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 7aa23ca15d..aad37a39ba 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -20,6 +20,8 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 /*
@@ -1284,7 +1286,7 @@ arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type)
 	ASSERT(BUF_EMPTY(hdr));
 	hdr->b_size = size;
 	hdr->b_type = type;
-	hdr->b_spa = spa_guid(spa);
+	hdr->b_spa = spa_load_guid(spa);
 	hdr->b_state = arc_anon;
 	hdr->b_arc_access = 0;
 	buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE);
@@ -2056,7 +2058,7 @@ arc_flush(spa_t *spa)
 	uint64_t guid = 0;
 
 	if (spa)
-		guid = spa_guid(spa);
+		guid = spa_load_guid(spa);
 
 	while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) {
 		(void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA);
@@ -2887,7 +2889,7 @@ arc_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bp,
 	arc_buf_t *buf = NULL;
 	kmutex_t *hash_lock;
 	zio_t *rzio;
-	uint64_t guid = spa_guid(spa);
+	uint64_t guid = spa_load_guid(spa);
 
 top:
 	hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp),
@@ -4522,7 +4524,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz)
 	boolean_t have_lock, full;
 	l2arc_write_callback_t *cb;
 	zio_t *pio, *wzio;
-	uint64_t guid = spa_guid(spa);
+	uint64_t guid = spa_load_guid(spa);
 	int try;
 
 	ASSERT(dev->l2ad_vdev != NULL);
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index a43b88338b..31ffd453f6 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -21,9 +21,8 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- */
-/*
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 /*
@@ -571,6 +570,43 @@ spa_prop_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
 	}
 }
 
+/*
+ * Change the GUID for the pool.  This is done so that we can later
+ * re-import a pool built from a clone of our own vdevs.  We will modify
+ * the root vdev's guid, our own pool guid, and then mark all of our
+ * vdevs dirty.  Note that we must make sure that all our vdevs are
+ * online when we do this, or else any vdevs that weren't present
+ * would be orphaned from our pool.  We are also going to issue a
+ * sysevent to update any watchers.
+ */
+int
+spa_change_guid(spa_t *spa)
+{
+	uint64_t	oldguid, newguid;
+	uint64_t	txg;
+
+	if (!(spa_mode_global & FWRITE))
+		return (EROFS);
+
+	txg = spa_vdev_enter(spa);
+
+	if (spa->spa_root_vdev->vdev_state != VDEV_STATE_HEALTHY)
+		return (spa_vdev_exit(spa, NULL, txg, ENXIO));
+
+	oldguid = spa_guid(spa);
+	newguid = spa_generate_guid(NULL);
+	ASSERT3U(oldguid, !=, newguid);
+
+	spa->spa_root_vdev->vdev_guid = newguid;
+	spa->spa_root_vdev->vdev_guid_sum += (newguid - oldguid);
+
+	vdev_config_dirty(spa->spa_root_vdev);
+
+	spa_event_notify(spa, NULL, FM_EREPORT_ZFS_POOL_REGUID);
+
+	return (spa_vdev_exit(spa, NULL, txg, 0));
+}
+
 /*
  * ==========================================================================
  * SPA state manipulation (open/create/destroy/import/export)
@@ -1773,7 +1809,7 @@ spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
 	    spa_guid_exists(pool_guid, 0)) {
 		error = EEXIST;
 	} else {
-		spa->spa_load_guid = pool_guid;
+		spa->spa_config_guid = pool_guid;
 
 		if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_SPLIT,
 		    &nvl) == 0) {
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index 1016ac7beb..c82dca6c56 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -1290,13 +1291,24 @@ spa_guid(spa_t *spa)
 	/*
 	 * If we fail to parse the config during spa_load(), we can go through
 	 * the error path (which posts an ereport) and end up here with no root
-	 * vdev.  We stash the original pool guid in 'spa_load_guid' to handle
+	 * vdev.  We stash the original pool guid in 'spa_config_guid' to handle
 	 * this case.
 	 */
 	if (spa->spa_root_vdev != NULL)
 		return (spa->spa_root_vdev->vdev_guid);
 	else
-		return (spa->spa_load_guid);
+		return (spa->spa_config_guid);
+}
+
+uint64_t
+spa_load_guid(spa_t *spa)
+{
+	/*
+	 * This is a GUID that exists solely as a reference for the
+	 * purposes of the arc.  It is generated at load time, and
+	 * is never written to persistent storage.
+	 */
+	return (spa->spa_load_guid);
 }
 
 uint64_t
diff --git a/module/zfs/vdev.c b/module/zfs/vdev.c
index 1630d2fae6..18d2d5ca6e 100644
--- a/module/zfs/vdev.c
+++ b/module/zfs/vdev.c
@@ -21,6 +21,8 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -291,6 +293,7 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 	if (spa->spa_root_vdev == NULL) {
 		ASSERT(ops == &vdev_root_ops);
 		spa->spa_root_vdev = vd;
+		spa->spa_load_guid = spa_generate_guid(NULL);
 	}
 
 	if (guid == 0 && ops != &vdev_hole_ops) {
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index a232ed0d58..65b0a19752 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -24,6 +24,10 @@
  * Portions Copyright 2012 Pawel Jakub Dawidek <pawel@dawidek.net>
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  */
+/*
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
+ */
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -1427,6 +1431,20 @@ zfs_ioc_pool_get_history(zfs_cmd_t *zc)
 	return (error);
 }
 
+static int
+zfs_ioc_pool_reguid(zfs_cmd_t *zc)
+{
+	spa_t *spa;
+	int error;
+
+	error = spa_open(zc->zc_name, &spa, FTAG);
+	if (error == 0) {
+		error = spa_change_guid(spa);
+		spa_close(spa, FTAG);
+	}
+	return (error);
+}
+
 static int
 zfs_ioc_dsobj_to_dsname(zfs_cmd_t *zc)
 {
@@ -4698,10 +4716,12 @@ static zfs_ioc_vec_t zfs_ioc_vec[] = {
 	    B_FALSE, POOL_CHECK_SUSPENDED | POOL_CHECK_READONLY },
 	{ zfs_ioc_obj_to_stats, zfs_secpolicy_diff, DATASET_NAME, B_FALSE,
 	    POOL_CHECK_SUSPENDED },
+        { zfs_ioc_pool_reguid, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+            POOL_CHECK_SUSPENDED | POOL_CHECK_READONLY },
 	{ zfs_ioc_events_next, zfs_secpolicy_config, NO_NAME, B_FALSE,
 	    POOL_CHECK_NONE },
 	{ zfs_ioc_events_clear, zfs_secpolicy_config, NO_NAME, B_FALSE,
-	    POOL_CHECK_NONE },
+	    POOL_CHECK_NONE }
 };
 
 int